1. Field of the Invention
This invention relates to nasal masks for delivering oxygen to a patient, and in particular, to nasal masks having nasal prongs.
2. Related Art
Patients today needing a continuous flow of oxygen, whether in a hospital or for home use, are limited as to the type of apparatuses available. At present, a patient receives oxygen through a conventional nasal cannula, see FIG. 1A showing the Prior Art, wherein oxygen is delivered to the patient's nostrils through a pair of one half inch long nasal prongs extending from a thin tubing—one prong being inserted in each nostril. The two ends of the thin tubing of the nasal cannula are connected to an oxygen source by a predefined length of conventional, thicker tubing. The nasal cannula is held in place on a patient by the thin tubing which is hung, or looped, around the patient's neck or ears. The nasal cannula is further held in place by sliding a small piece of plastic attached to the thin tubing toward the patient's head and neck, wherein both ends of the thin tubing are inserted through the piece of plastic. As the piece of plastic gets close to the patient's head and neck, the tighter the tubing becomes, thereby holding the nasal prongs within the patient's nostrils. The piece of plastic is held in position on a desired point of the thin tubing of the nasal cannula by friction.
There are many disadvantages with a conventional nasal cannula. First, the nasal prongs are only one half of an inch in length. Although this short length appears to be for the comfort of the patient, it is very inefficient in the delivery of oxygen. That is, because the nasal prongs are so short, the nasal prongs do not fit well within a patient's nostrils such that part of the oxygen escapes out of the patient's nostrils.
Second, the short length of the nasal prongs causes the nasal prongs to fall out of the patient's nostrils very easily. This is especially true when a patient makes the slightest turn of his/her head.
Third, the fastening mechanism of a conventional nasal cannula is very weak. The nasal cannula is held in place by simply looping the thin tubing around the patient's neck or ears and sliding a small piece of plastic into place. As a result, the nasal prongs are easily pulled out of the patient's nostrils, which typically happens during sleep.
Accordingly, conventional nasal cannulas are very ineffective because patients do not receive oxygen in the same concentrations as needed. Therefore, there is a need for a nasal mask assembly that provides a patient with a continual and constant flow of oxygen in the needed concentration. There is a further need for a nasal mask assembly using nasal prongs that is flexible and capable of maintaining its position on a patient even when the patient moves and turns his/her head.
Several United States patents attempted to solve the problems associated with delivering oxygen, or other fluid, e.g., breathable air or an anesthesia, to a patient. However, none of these prior patents provide a simple solution for a patient, and all of these prior art patents are cumbersome and very intrusive to a patient. For example, in U.S. Pat. No. 5,348,000 (“the '000 patent”), an apparatus is disclosed having an interchangeable facemask and nasal catheter. That is, a facemask is inserted in the flow of fluid, e.g., anesthesia, between an anesthesia machine and the nasal prongs of a nasal catheter. With this arrangement, a physician can switch easily between using the nasal catheter and a facemask on a patient without having to reconfigure the anesthesia machine.
Although the '000 patent benefits physicians during minor surgeries, the apparatus of the '000 patent does not provide any advantage to a patient requiring a constant and uninterrupted flow of oxygen. A patient would have to choose between using the nasal prongs of a conventional nasal catheter or the face mask. There is absolutely no way that a patient would be able to use both the nasal prongs with the face mask. Thus, a patient experiences the same disadvantages with the apparatus of the '000 patent that he/she experiences using a conventional nasal cannula.
In U.S. Pat. No. 5,537,994 (“the '994 patent”), a combination face mask and dental device is disclosed to improve a person's breathing during sleeping. The dental device is attached to the face mask such that the dental device acts as an anchor to maintain the placement and position of the face mask on the patient. As with other devices, the face mask is connected to a constant positive air pressure (CPAP) system by conventional means. There are several obvious disadvantages with the device of the '994 patent: a patient could only use this device while sleeping because it would interfere with talking and eating; the dental device is very cumbersome and awkward to use; and there is no direct flow of air into the patient's nostrils.
In U.S. Pat. No. 6,012,455 (“the '455 patent”), another dentally stabilized nasal mask is disclosed. The device is functionally similar to the device of the '994 patent, and thus, suffers from the same disadvantages.
In U.S. Pat. No. 6,192,886 (“the '886 patent”), a nasal mask is disclosed having sealing flanges extending around the rim for forming an air-tight seal during use. The principal disadvantage of this nasal mask is that it requires the patient to wear a cap that has straps for attaching to the sealing flanges of the mask. The need for a cap and straps is very cumbersome and would be extremely uncomfortable to wear for extended periods of time. Also, the nasal mask of the '886 patent does not use nasal prongs, resulting in a patient not receiving a direct flow of oxygen into his/her nostrils.
Therefore, there is a need for a simple nasal mask assembly that is comfortable for a patient to wear for extended periods of time, is flexible such that it moves easily with a patient without moving or slipping out of position, is capable of providing a patient with a constant flow of oxygen, or other fluid, directly into the patient's nostrils, and does not interfere with the patient's eating or talking.